AnswersCA-The Living Earth A-CRLab: Natural Selection-Standard Bio 4.2

Factors Affecting Genetic Variation Answers

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1
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Which of the following best defines gene flow?

A
the sum of all genetic traits in a population’s individuals at a given time
B
any movement of genes from one population to another
C
any movement of organisms from one environment to another
D
the random change in the frequency of an allele in a population
2
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Which environmental factor could lead to a decrease in genetic variation in a population of tuna?

A
an increase in food availability
B
an increase in pollution
C
a decrease in tuna fishing
D
a decrease in tuna predators
4

Which term best describes the difference in colors of the birds below?

Question illustration
A
natural selection
B
reproductive maturity
C
genetic variation
D
genetic drift
5

Genetic drift in a population affects the gene pool in which of the following ways?

A
decrease in genetic variation
B
increase in genetic variation
C
increased in mutations
D
decreased in gene flow
6

Which environmental factor would likely lead to an increase in genetic variation in a population of squirrels?

A
an increase in predators
B
an increase in available food
C
an increase in forest fires
D
an increase in pollution
9

A population of snakes that eat small rodents enters a new habitat. In the new habitat, there are many species of rodents, and their populations are high because there are few natural predators. What will most likely be the effect on the genetic variation of the snake population?

A
Genetic variation will increase because of a selective pressure.
B
Genetic variation will increase because of a new habitat and food source.
C
Genetic variation will decrease because of a selective pressure.
D
Genetic variation will decrease because of a new habitat and food source.
11

A high population of greater prairie chickens once inhabited the prairies of Illinois. The conversion of the prairies into agricultural land caused the chickens to lose their habitat. Studies have concluded that this change greatly reduced the greater prairie chicken population. The habitat loss also resulted in a decrease in the population’s genetic variation.Which change in the gene pool occurred in the greater prairie chicken population?

A
gene mutation
B
gene flow
C
genetic drift
D
genetic resistance
12

A group of students is walking in the park, and one of them takes a picture of a pollen grain that is being blown by the wind. What caption can the student use for this picture?

A
gene mutation in action
B
gene flow at work
C
genetic drift as it happens
D
natural selection in progress
13

Environmental factors can influence natural selection because they can increase or decrease

A
the number of chromosomes in an individual.
B
the number of chromosomes in a population.
C
the amount of genetic variation in an individual.
D
the amount of genetic variation in a population.
14

Which would most likely result in an increase in genetic variation in a population?

A
an increase in predators and a decrease in food
B
an increase in predators and an increase in food
C
a decrease in predators and an increase in food
D
a decrease in predators and a decrease in food
15

In a few generations, this population of beetles changed. Which is the most likely explanation for the change?

Question illustration
A
The beetle population moved to a greener habitat.
B
A natural disaster almost caused the extinction of the population.
C
The beetle population’s food sources decreased dramatically.
D
A mutation resulted in a new color of insect.

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